Wort pH

General Considerations

High wort pHs should be avoided because of extraction of excessive amounts of undesirable substances such as tannins, silicates, polyphenols etc.

The mineral composition of brewing liquor has a demonstrable effect on wort pH.

Range of Values

The acceptable range for the pH of boiled worts for cask conditioned beers is 5·0 – 5·3 units. However, a large variance is possible between the pH of strong (approximately 4·9) and weak worts (5·4 – 5·6).

When wort is boiled the pH falls usually by in the order of 0·05 – 0·15 units.

Operational Protocols

At least monthly, and when starting a new season’s malt or changing supplier, the pH should be measured of first and last runnings, of copper wort at make-up, and in fermentation at collection and on reaching the attenuation target.

Measurement Protocols

pH measurement to ± 0·1 units requires daily calibration of the pH meter and either a fixed temperature for measurement or automatic temperature compensation.